Food, both in edible and drinkable forms, plays several roles in the Half-Life and Portal universe. They can either play an aesthetic role, giving more depth to the universe, or be of use to the player. They sometimes have a specific brand.

The Anomalous Materials facility features a small cafeteria with a microwave oven in which the player can ruin the meal, revealed later to have been a casserole belonging to Arne Magnusson.

Sector D features a cafeteria in the Administration Offices. Early in the game's development, the humorous idea of a food fight was proposed to occur in the there, idea eventually rejected.[1] The cafeteria has a large walk-in freezer which stores a number of hanging slabs of beef.

Coffee is commonly drunk by Black Mesa employees. Coffee machines are seen several times in food courts, and scientist sometimes ask if someone has seen their coffee cup.

Beer is also drunk by personnel, as security guards sometimes promise a beer to Freeman if they meet again, retconned as said by Barney Calhoun only.

Some security guards are fond of donuts, which is sometimes mocked by scientists. In the shooting range of the Area 3 Medium Security Facilities, a security guard is humorously seen holding a donut with his right hand, while trying to get his gun with the left hand, instead of simply putting the donut in the left hand, and grabbing his gun with the right hand.

Water affects the memory of Citizens, as said by a Citizen in the City 17 Trainstation at the start of Half-Life 2: "Don't drink the water. They put something in it to make you forget. I don't even remember how I got here.".

Vending machines of "Dr. Breen's Private Reserve" (">B") can be seen around City 17. Similar to the Black Mesa vending machines, they also deliver cans, but they don't give health points to the player. Cans come in blue, red and yellow colors.

Several fruits and vegetables are seen throughout the games. Watermelons are seen prominently, and can be torn apart by the Gravity Gun; they also seem to be the diet of Lamarr as seen on Kleiner's Lab corkboard. The Black Mesa East kitchen also features carrots, red onions, herbs, a bag of beans, some sort of stew / soup. Pumpkins can be found on the Outskirts, and function the same as watermelons.

The cake is featured prominently in Portal, as it is promised by GLaDOS to Chell for when she concludes the tests. The quote "The cake is a lie." by Doug Rattmann has become very famous in the popular culture since then. A cake recipe is also frequently seen on monitors.

The Ratman dens feature several food and drink containers of water, milk and beans.

In Portal 2, GLaDOS is attached by Wheatley to a potato battery, capable of powering only her consciousness and most basic functions. The potato-based energy is introduced earlier, in the "Bring your Daughter to Work Day" experiments found in the Employee Daycare Center.

In the second Enrichment Sphere of Test Shaft 09, it is heard in the announcements that before the test Test Subjects were given coffee containing fluorescent calcium so that the staff can track the neuronal activity in their brains.

Near the end of Test Shaft 09 Cave Johnson goes mad and ends up going on an illogical rant about lemons.